Abstract: A system of checks and balances is the basic institutional arrangement of American democratic politics.It plays an important role in preventing political tyranny,balancing diversified interests and enhancing decision-making prudence.However, this institutional arrangement requires sacrificing decision-making efficiency.In recent years, the views of the two major political parties—the Democrats and the Republicans—have become polarized.The presidency and the two houses of Congress are often controlled by different parties.The antagonism between the political parties has resulted in a “vetocracy.” The benefits of the American government's decentralized system have decreased,while the costs have risen remarkably.This has caused the operation of American democracy and state governance to be negatively impacted.To solve this problem,in theory,we can adopt the idea of reducing the opposition of the political parties without touching the institutional arrangement of checks and balances.We also can adopt the institutional reform paths of adjusting the legislative checks and balances between the U.S.Senate,the House of Representatives and the President, or changing the presidential system to a parliamentary system.In reality, the possibility of changing the institutional arrangement of checks and balances is very unlikely-unless institutional costs rise to a point that American society cannot afford.